Switching and aggregation of small cell wireless traffic

ABSTRACT

A small cell controller for switching and aggregating wireless data between a cellular network and a noncellular network is disclosed. The small cell controller may include a cellular interface to communicate data with the cellular network, a noncellular interface to communicate data with the noncellular network, and an analyzer configured to determine whether a portion of the wireless data may be transferred from the cellular network to the noncellular network, and determine a first portion of the noncellular network to be allocated to the portion of the wireless data when the portion of the wireless data may be transferred.

TECHNICAL FIELD

The present disclosure relates generally to methods and systems forswitching and aggregating small cell wireless traffic.

BACKGROUND

Various wireless technologies (e.g., 3G, 4G, 3GPP Long Term Evolution(LTE), LTE-Advanced (LTE-A), WiMAX, etc.) allow for the use of small,user installed, base stations, generally referred to herein as smallcells (e.g., femtocells in WiMAX or Home node-B in 3GPP). The small cellis provided to the user by a wireless service provider. The user or awireless service provider's technician installs the small cell in theuser's home or office, generally referred to herein as a home or homelocation, to increase the signal quality and strength of the localwireless coverage. The small cell's backhaul connection to the wirelessservice provider's network is provided via the user's home networkaccess (e.g., DSL). The small cell operates in a similar wirelessfashion (e.g., uses the same licensed frequency band) to the wirelessservice provider's other base stations (e.g., macro base stations (MBSs)and/or relay stations). The small cell may allow for the handover fromthe MBS to the small cell to be done without the user noticing (e.g.,similar to the handover from one MBS to another).

An additional advantage of small cells is that they may be able toassist in handling excess data traffic apart from the wireless serviceprovider's base stations, thus lessening the load on the base stationand improving performance for the user. However, as the number andimportance of small cells increase, the density of small cells within ageographic area also increases. Thus, it has become increasinglyimportant to account for this increased density when determining smallcell performance.

SUMMARY

A small cell controller for switching and aggregating wireless databetween a cellular network and a noncellular network is disclosed. Thesmall cell controller may include a cellular interface to communicatedata with the cellular network, a noncellular interface to communicatedata with the noncellular network, and an analyzer configured todetermine whether a portion of the wireless data may be transferred fromthe cellular network to the noncellular network, and determine a firstportion of the noncellular network to be allocated to the portion of thewireless data when the portion of the wireless data may be transferred.

Technical advantages of the present disclosure may be readily apparentto one skilled in the art from the figures, description and claimsincluded herein. The objects and advantages of the embodiments will berealized and achieved at least by the elements, features, andcombinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example system for switching and aggregatingwireless signals, in accordance with certain embodiments of the presentdisclosure;

FIG. 2 illustrates an example allocation of bandwidth between thelicensed and unlicensed bands for a given SUE, in accordance withcertain embodiments of the present disclosure;

FIG. 3 illustrates a block diagram of a system for switching and/oraggregating communication over the licensed and/or unlicensed bands, inaccordance with certain embodiments of the present disclosure;

FIG. 4 illustrates an example signaling diagram for supporting theswitching and/or aggregation operations, in accordance with certainembodiments of the present disclosure; and

FIG. 5 is a flowchart of an example method for determining whether auser equipment should have traffic switched to an unlicensedcommunication band, in accordance with certain embodiments of thepresent disclosure; and

FIG. 6 is a flowchart of an example method for determining whether auser equipment should have traffic aggregated with traffic in anunlicensed communication band, in accordance with certain embodiments ofthe present disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates an example system 100 for switching and aggregatingwireless signals, in accordance with certain embodiments of the presentdisclosure. In some embodiments, system 100 may include one or moremacro base station(s) (“MBS”) 102, one or more macro user equipment(s)(“MUE”) 104, one or more small cell evolved node B(s) (“SeNB”) 106, oneor more small cell user equipment(s) (“SUE”) 108, and one or more smallcell node(s) (“SN”) 110.

In some embodiments, MBS 102 may be a cellular transmission tower suchas those operated by cellular service providers. For example, MBS 102may be a cellular transmission tower configured to transmit cellulardata that complies with the 3d Generation Partnership Project (“3GPP”)protocol(s). In the example illustrated in FIG. 1, MBS 102 may beconfigured to transmit cellular data that complies with the Long TermEvolution (“LTE”) standard based on Release 8 of 3GPP. In the same oralternative embodiments, MBS 102 may be configured to transmit cellulardata that complies with other cellular protocols, including laterreleases of 3GPP or other fourth- (or later) generation protocols suchas LTE-A.

In some embodiments, MBS 102 may be configured to transmit cellular datato one or more MUE(s) 104. MUE 104 may be any electronic deviceconfigured to receive and/or transmit cellular data from MBS 102. Forexample, MUE 104 may be a cellular telephone, cellular modem, or otherdevice configured to communicate with MBS 102.

System 100 may also include one or more small cell controller(s), e.g.,Small eNode B (“SeNB”)(s) 106. In some embodiments, SeNB 106 may be anyelectronic device configured to switch and/or aggregate cellular andwireless data for communication among other device, as described in moredetail below with reference to FIGS. 2-6. For example, SeNB 106 may bean electronic device configured to provide load balancing between thecellular communication path provided by MBS 102 and a private WiFicommunication path. In some embodiments, SeNB 106 may include memory andone or more processor(s) configured to execute instructions stored onthat memory. As described in more detail below with reference to FIGS.2-6, SeNB 106 may be configured to execute instructions performing theoptimization routines discussed below. In other configurations,responsibilities for various portions may be distributed among thecomponents of system 100. For example, in legacy configurations of asmall cell controller, it may be necessary to include a node separatefrom a radio network controller.

In some embodiments, it may be necessary or desirable for a home orbusiness to have one or more small cells deployed throughout the home orbusiness. These small cells may be electronic devices configured toroute data to a cellular provider's core network over a broadband orother communication link. In such a manner, a cellular provider mayextend coverage of the cellular network indoors or to areas which mightbe more difficult to reach via conventional cellular radiationtechniques. In some embodiments, the small cell may communicate with thecellular provider's core network over a wireline link such as DSL,optical fiber, or other appropriate wireline link, or a wireless linksuch as a wireless local area network (“WiFi”). Electronic deviceswithin the home or business may then be able to connect to the WiFinetwork (and subsequently the cellular provider's core network) via oneor more non-cellular connection(s). In some embodiments, this may bebeneficial to both the user and the wireless service provider. Whensmall cells are active, the user, the user equipment, the radio accessnetwork, or some combination thereof may be able to offload some portionof the cellular data traffic onto the local area network forcommunication back to the core network. This may have the benefit oflowering the traffic level on the wireless base stations as well asimproving performance for the user.

In some existing configurations of small cells, this “data offload”process may be performed by a number of different approaches. Forexample, Local IP Access (“LIPA”) uses a femtocell to enable a user tooffload all traffic onto the local area network. Selected IP TrafficOffload (“SIPTO”) is another data offload approach. Under this approach,internet traffic can flow from the femtocell directly to the internet,thereby bypassing the wireless service provider's core network. Yetanother approach is IP Flow Mobility and Seamless Offload (“IFOM”). Thisapproach leverages the user equipment to determine which communicationmethod to use. However, this method relies on user action in order tooffload traffic.

The approach described in more detail below with reference to FIGS. 1-6illustrates a data offloading and optimization approach that istransparent to the user, takes advantage of both cellular andnoncellular communication paths, and, in some embodiments, consolidatesprocessing into the small cell controller.

Referring again to FIG. 1, in some embodiments, at least two types ofelectronic devices may be configured to connect to SeNB 106. SUE 108 maybe an electronic device configured to communicate over either or both ofa cellular and a WiFi communication path. For example, a cellulartelephone, tablet computer, laptop computer, or other appropriateelectronic device may be configured to transmit and/or receive data overa cellular and/or WiFi communication path. In the same or alternativeembodiments, system 100 may also include one or more SN(s) 110. SN 110may be an electronic device configured to communicate only over a WiFicommunication path. For example, SN 110 may be a laptop computer orother device configured to communicate only over a WiFi communicationpath.

In operation, there may be a number of users attempting to access acellular provider's core network within a given area. As described inmore detail above, the implementation of small cells may be one methodto alleviate traffic congestion. In an area with a number of such smallcells, it may be necessary or desirable to manage the interferencebetween the small cells and MBS 102 (as well as manage the interferenceamong small cells) in order to optimize data traffic. As described inmore detail below with reference to FIGS. 2-6, SeNB 106 may beconfigured to optimize the balancing of data between the cellularcommunication path(s) among MUE 104 and MBS 102; the cellularcommunication path(s) among SUE 108 and SeNB 106; the wirelesscommunication path(s) among SUE 108 and the local area network; and thewireless communication path(s) among SN 110 and the local area network.In some embodiments, SeNB 106 may perform this optimization through amixture of admission control, resource allocation, and/or packetscheduling.

Although FIG. 1 illustrates example system 100 as having one MBS 102,three MUE 102, 1 SeNB 106, three SUE 108, and three SN 110, it should beunderstood that these example are provided to aid in understanding andany number of any given component may be present in a givenconfiguration without departing from the scope of the presentdisclosure. It should also be understood that the number of any givencomponent may change over time. For example, the number and identity ofSUE 108 present within range of a given SeNB 106 may change over time asusers move into and out of the space designed to be serviced by SeNB106.

Further, although FIG. 1 illustrates only one iteration of the systemcomprising MUE 104, SeNB 106, SUE 108, SN 110, a number of suchiterations may be present within system 100 without departing from thescope of the present disclosure. For example, there may be a pluralityof SeNB 106 present within range of a given MBS 102. In otherembodiments, system 100 may not include MBS 102. In those or alternativeembodiments, there may instead be a cascade (or other dependentconfiguration) of a plurality of SeNB 106. For example, a business maywish to outfit a large building with multiple small cells. In such aconfiguration, it may be necessary or desirable to communicativelycouple one SeNB 106 to another in order to further communicativelycouple SeNB 106 to a remotely located MBS 102 or other data provider.

Still further, although FIG. 1 illustrates example system 100 asemploying cellular communication between MBS 102 and user equipment, andwireless communication between SeNB 106 and user equipment, othercommunication protocols may be implemented in any given configurationwithout departing from the scope of the present disclosure. For example,SeNB 106 may connect user equipment to the cellular provider's corenetwork via ethernet or other hard-wired communication mechanisms, aswell as any appropriate communication protocol, standard, and/orimplementation. In the more detailed description below with reference toFIGS. 1-6, the communication path(s) between MBS 102 (or otherappropriate communication device) and user equipment may be genericallyreferred to as communication within the “licensed band” or “cellularnetwork.” The communication path(s) between SeNB 106 and SUEs 108 overthe licensed band may be generically referred to as communication withinthe “licensed band” or “cellular network.” The communication path(s)between SeNB 106 and SUEs 108 or SNs 110 over a license-exempt band maybe generically referred to as communication within the “unlicensedband.”

Although reference is made above and below with reference to FIGS. 2-6to LTE as the licensed band technology and WiFi as the unlicensed bandtechnology, other technologies, standards, and/or protocols may beimplemented without departing from the scope of the present disclosure.For example, the systems and methods described herein may also beapplied to WiMAX as another licensed cellular technology with OFDMtransmission. As a further example, one of ordinary skill in the artwould recognize that the switching and aggregation of data betweenlicensed band technologies and WiFi disclosed herein may be applied toTV white spaces (IEEE802.22) as the unlicensed band technology.

FIG. 2 illustrates an example allocation 200 of a plurality of resourceblocks of bandwidth used for licensed bands shared by both MBS 102 andSeNB 106 normalized over one subframe in time, in accordance withcertain embodiments of the present disclosure. Example allocation 200may be understood to represent multiple resource blocks in frequencyalong a frequency axis. Allocation 200 may then be understood torepresent a snapshot of frequency allocation versus frequency. Thefrequency blocks may then be shared between MBS 102 and SeNB 106 asdescribed in more detail below.

In the example allocation 200, licensed bandwidth is allocated between(1) a communication path between MUE 104 and MBS 102, and (2) acommunication path between SUE 108 and SeNB 106. These are representedby bandwidth allocation regions 202, 204, respectively. For example, asdescribed in more detail below and with reference to FIGS. 3-6,allocation region 202 may include a plurality of sub-regions 206, witheach sub-region 206 corresponding to a data communication request (e.g.,a request for a particular service) between MUEs 104 and MBS 102.Likewise, allocation region 204 may include a plurality of sub-regions208, with each sub-region 208 corresponding to a data communicationrequest (e.g., a request for a particular service) between SUEs 108 andSeNB 106.

In some embodiments, there may be interference between the communicationhandled by MBS 102 and SeNB 106. One approach to managing thisinterference may be to define a preset allocation between allocationregions 202, 204. However, such an approach may be unable to takeadvantage of unused bandwidth. For instance, if the allocation betweenallocation regions 202, 204 were fixed, the data communication requestsfor a given allocation region 202, 204 may not require the entirety ofthe allocation. In such a case, bandwidth may be wasted. As described inmore detail below and with reference to FIGS. 3-6, another approach tomanaging interference may be to dynamically adjust the allocation of thelicensed bandwidth between allocation regions 202, 204 based on thecurrent needs of users. For example, if MUEs 104 require less data at agiven point in time, allocation 200 may allot less bandwidth toallocation region 202 while allotting more bandwidth to allocationregion 204 so that SUEs 108 may take advantage of the availablebandwidth. Moreover, although the preset allocation approach results inno inter-cell interference between MBS 102 and SeNB 106, this isconsidered a very conservative approach as MUEs 104 and SUEs 108 mightbe tolerant to a certain level of interference.

In some embodiments, system 100 may accomplish this dynamic allocationbased on an analysis of a plurality of characteristics of system 100, asdescribed in more detail below and with reference to FIGS. 3-6. Forexample, system 100 may undertake a probability-based analysis in orderto determine the fraction of the licensed bandwidth to allocate toallocation regions 202, 204. In some embodiments, SeNB 106 and/or MBS102 may apply the results of this analysis to select the appropriateradio resource blocks to transmit over the appropriate communicationchannel(s).

The dynamic allocation of allocation regions 202, 204 may be constrainedby a variety of factors, as described in more detail below and withreference to FIGS. 3-6. In some embodiments, one such constraint may bethe quality of service (“QOS”) requirement(s) of a particular userequipment making a particular data communication request. For example,TABLE 1 below illustrates a number of data communication requests, alongwith an example QOS requirement for each.

TABLE 1 Packet Packet Delay Error Resource Budget Loss Example QCI TypePriority (ms) Rate Services 1 GBR 2 100 10⁻² Conversational Voice 2 GBR4 150 10⁻³ Conversational Voice (live streaming) 3 GBR 3 50 10⁻³ RealTime Gaming 4 GBR 5 300 10⁻⁶ Non-Conversational Video (bufferedstreaming) 5 Non-GBR 1 100 10⁻⁶ IMS Signalling 6 Non-GBR 6 300 10⁻⁶Video (buffered streaming), TCP- based (e.g., www, e- mail, chat, ftp,etc.) 7 Non-GBR 7 100 10⁻³ Voice, Video (Live Streaming), InteractiveGaming 8 Non-GBR 8 300 10⁻⁶ Video (buffered streaming), TCP- based(e.g., www, e- mail, chat, ftp, etc.) 9 Non-GBR 9 300 10⁻⁶ Video(buffered streaming), TCP- based (e.g., www, e- mail, chat, ftp, etc.)

The examples provided in TABLE 1 illustrate the variety of data resourcerequests that may be required of an implementation of system 100. Forexample, system 100 may be required to support a service that requires aguaranteed bit rate (“GBR”) and thus low latency but is tolerant of dataerror (e.g., conversational voice), as well as services that aretolerant of latency while intolerant of error rate (e.g., TCP-basedservices such as FTP).

These QOS requirements for the various data services act as a constrainton the amount and type of bandwidth that may be allocated to aparticular user of system 100. Additionally, the needs of a particularuser may change over time. Referring again to FIG. 2, the QOSrequirements for a data service may constrain the allocation of thetotal licensed bandwidth allocated to allocation regions 202, 204. Insome embodiments, the allocation may include an analysis of the fractionof total licensed bandwidth that should be allocated to allocationregion 204—for communication with SeNB 106. This may include an analysisof what fraction of the total licensed bandwidth should be assigned to aparticular SUE 108. FORMULAS 1-2 below illustrate one mechanism fordetermining this fraction.

$\begin{matrix}{R_{ld}^{(i)} = {\alpha_{i}B_{d}\eta_{b}{\eta_{c}\left\lbrack {{\alpha_{m}{\log_{2}\left( {1 + \frac{P_{s}{g_{i}}^{2}}{\left( {N_{o\; l} + {P_{m}{J_{i}}^{2}}} \right)\eta_{s}} + {\left( {1 - \alpha_{m}} \right){\log_{2}\left( {1 + \frac{P_{s}{g_{i}}^{2}}{N_{o\; l}\eta_{s}}} \right)}}} \right\rbrack}} = {\alpha_{i}B_{d}\psi_{ld}^{(i)}}} \right.}}} & {{FORMULA}\mspace{14mu} 1} \\{\mspace{79mu}{\alpha_{m} = {\sum\limits_{j = 1}^{M}\alpha_{m}^{(j)}}}} & {{FORMULA}\mspace{14mu} 2}\end{matrix}$

In FORMULAS 1-2 above, the average rate of a given SUE 108 in thelicensed band in downlink, as represented by the parameter R^((i))_(ld), is determined. This term is calculated from a number of otherparameters, including α_(i), a fraction of bandwidth allocated to SUE108 from the licensed band in the downlink stage of communication. InFORMULAS 1-2 above, R_(d) represents the total system bandwidth in thelicensed band in the downlink. R^((i)) _(ld) represents the average rateof the SUE indicated by the index counter i in the licensed band in thedownlink.

In reference to FORMULA 1 above, the term between the square bracketsmay represent the average spectral efficiency. With a probability α_(m),a certain physical resource block will be used by MBS 102. Thus, if thisphysical resource block is used by SeNB 106 it may suffer frominterference from MBS 102 as in the first term between brackets in thefirst line of FORMULA 1. There is also a probability 1−α_(m) that aphysical resource block is not used by MBS 102 and thus no interferencemay be considered in the denominator of the second term of FORMULA 1.

As described in more detail below with reference to FIGS. 2-6, thesevalues may be calculated within (or external to, depending on theparticular configuration) system 100 and used by the appropriatecomponent to determine the average rate for a given SUE 108.

As described in more detail above and with reference to FIG. 1,interference among SeNBs 106 and MBS 102 may affect the performance ofan optimization system. The approach illustrated with FIGS. 1-2addresses this potential interference. The term P_(s) represents thetransmit power per physical resource block of SeNB 106. The term P_(m)represents the transmit power per physical resource block of MBS 102.The term |g_(i)|² represents the channel power in downlink between SeNB106 and the particular SUE 108 denoted by the index i. The term |J_(i)|²represents the interference power in downlink between MBS 102 and theparticular SUE 108 denoted by the index i.

The three parameters η_(b), η_(c), and η_(s) may be used in the designof system 100 for modeling the throughput of a practical system. Forexample, the first may represent the system bandwidth efficiency, whilethe second two may be jointly used to model existing efficiencies due toreceiver algorithms and supported modulation and coding schemes. Asdescribed in more detail above with reference to FIG. 1, it may benecessary or desirable to implement system 100 within existing smallcells. The use of these parameters in the design of system 100 may allowthe system designer to account for existing design attributes. Forexample, in simulating a SISO system, a system designer may use thevalues η_(b)=0.42, η_(c)=1, and η_(s)=0.62.

In addition to the parameters described above, it may also be necessaryor desirable in some embodiments to model the noise power per physicalresource block in the licensed band. In FORMULAS 1-2, this isrepresented by the parameter N_(ol). FORMULA 1, therefore, calculatesthe average downlink rate for a given SUE 108 based on the fraction ofbandwidth assigned to that SUE 108 in downlink (α_(i)), the total systembandwidth in the licensed band in downlink (B_(d)), and the averageeffective spectral efficiency obtained by that SUE 108 (ψ_(ld) ^((i))).

Similar to the approach taken for SUE 108, the average rate for MUE 104in the licensed band in downlink may be determined. FORMULA 3 belowillustrates an example method for determining this rate.

$\begin{matrix}{R_{md}^{(i)} = {\alpha_{m}B_{d}\eta_{b}{\eta_{c}\left\lbrack {\alpha_{s}{\log_{2}\left( {1 + \frac{P_{m}{h_{j}}^{2}}{\left( {N_{o\; l} + {P_{s}{I_{j}}^{2}}} \right)\eta_{s}} + \left. \quad{\left( {1 - \alpha_{s}} \right){\log_{2}\left( {1 + \frac{P_{sm}{h_{j}}^{2}}{N_{o\; l}\eta_{s}}} \right)}} \right\rbrack} \right.}} \right.}}} & {{FORMULA}\mspace{14mu} 3} \\{\mspace{79mu}{\alpha_{s} = {\sum\limits_{i = 1}^{S\; 1}\alpha_{i}}}} & {{FORMULA}\mspace{14mu} 4}\end{matrix}$

In addition to the parameters described above, FORMULAS 3-4 alsodescribe the parameter S₁, the number of SUEs 108. They also describethe parameter |h_(j)|², which represents the channel power between MBS102 and a given MUE 104 in downlink. Likewise, |I_(j)|² represents theinterference power between SeNB 106 and a given MUE 104 in downlink. Insome embodiments, the value of |h_(j)|² may be reported from MBS 102from a report sent from MUE 104 to MBS 102 as part of its ordinaryoperation. An estimation of |I_(j)|² may be made from sounding referencesignals monitored as part of the ordinary operation of MBS 102. SeNB 106may use the sounding signals to estimate the path loss in the uplinkdirection and to estimate the path losses in the downlink. For example,when SeNB 106 overhears sounding signals, it may get estimates of thepath loss in the uplink direction from MUEs 104 to SeNB 106. Using theestimates of uplink path losses, SeNB 106 may calculate estimates of thepath losses in the downlink. These estimates may be more accurate whenusing Time Division Duplex operation modes.

In some embodiments, it may be necessary or desirable to maximize thesum rate of all SUEs 108 within system 100 such that the rate of a givenMUE 104 is higher than a predefined threshold value (e.g., the parameterr_(m) ^((j)) of FORMULA 5 below, representing a predefined minimum rate)for all MUEs 104 within the vicinity of SeNB 106. In order to maximizethis rate, one approach is to use a linear programming routine tomaximize α_(i) (the fraction of bandwidth in the licensed band indownlink assigned to a given SUE 106) subject to a series ofconstraints, as illustrated by FORMULA 5 below.

$\begin{matrix}\begin{matrix}{{Maximize}\mspace{14mu}\left\{ \alpha \right\}} & {\sum\limits_{i = 1}^{S_{1}}{\alpha_{i}B_{d}\psi_{ld}^{(i)}}} \\{{subject}\mspace{14mu}{to}} & {{R_{md}^{(j)} \geq {\overset{\_}{r}}_{m}^{(j)}},{j = 1},\ldots\mspace{14mu},M} \\\; & {{{\sum\limits_{i = 1}^{S_{1}}\alpha_{i}} \leq {\overset{\_}{\alpha} - \alpha_{m}}} = \overset{\_}{\alpha_{s}}} \\\; & {{0 \leq \alpha_{i} \leq 1},{i = 1},\ldots\mspace{14mu},S_{1}}\end{matrix} & {{FORMULA}\mspace{14mu} 5}\end{matrix}$

In this example approach, the first constraint may represent the QOSrestraints for MUEs 104 as described in more detail above with referenceto FIG. 2. The second constraint may put an upper limit (a_(s) ) on thesum of bandwidth fractions assigned to all SUEs 108. This upper limitmay be a function of a parameter (α) that may control how much sharingof bandwidth between SeNB 106 and MBS 102 is allowed. In someembodiments, α may range from 1 to 1+α_(m), leading to a range of valuesfor α_(s) of 1−α_(m) to 1. This may allow the designers of system 100 tocontrol the level of interference of the downlink transmission of SeNB106 on MUE(s) 104 and the level of interference of the downlinktransmission of MBS 102 on SUE(s) 108.

In addition to optimizing intercell interference in the licensed band indownlink, it may also be necessary or desirable in some embodiments tooptimize the downlink in both the licensed and unlicensed bands. In thelicensed band, resources may be allocated to user equipment by the smallcell controller in a centralized, orthogonal and non-overlapped fashionin both frequency and time. In the unlicensed band, however, usage maybe more unpredictable and non-controllable. In this case, the userequipment may demand the resource when data communication is required inan on-demand and distributed manner. In the case of the unlicensed band,all users may contend on the communications channel and when a userseizes the channel it takes the entire bandwidth for a certain amount oftime before releasing the channel.

In some embodiments, when optimizing the switching and/or aggregation ofboth licensed and unlicensed band communication, system 100 may takeadvantage of opportunistic scheduling whenever the resource in theunlicensed band becomes available. Depending on the particularconfiguration of the unlicensed band system, the throughput through thesmall cell controller (e.g., SeNB 106) may be dependent on the number ofdevices contending for access to the wireless medium. Referring again toFIG. 1, system 100 may include a number of SNs 110 (represented by theparameter S₂), a number of SUEs 108 (represented by the parameter S₁),as well as SeNB 106 itself. Therefore, if all S₁ SUEs 108 are havinguplink transmissions on the unlicensed band, the total number of devicescontending for access to the wireless medium may be represented by theparameter n=S₁+S₂+1. The parameter n may therefore range from S₂+1 toS₁+S₂+1 depending on the number of SUEs 108 accessing the unlicensedband in the uplink.

FORMULA 6 below illustrates one approach for determining the throughputthat a device may be able to achieve using a wireless interface. Thisformula makes use of the parameters τ and p. The former represents theprobability of collision between data requests from a given one of the nnodes contending for the communication channel on the unlicensed band.The latter represents the probability of transmission of a given SUE108, SN 110, SeNB 104 in a random time slot. In an example model inwhich all communication channels are homogeneous and the system issaturated, the throughput may be determined as illustrated in FORMULA 6.

$\begin{matrix}{R_{WIFI} = \frac{{\tau\left( {1 - \tau} \right)}^{n - 1}L_{i}}{\begin{matrix}{{\left( {1 - \tau} \right)^{n}\sigma} + {{n_{\tau}\left( {1 - \tau} \right)}^{n - 1}\left( {T_{s} - T_{c}} \right)} +} \\{\left( {1 - \left( {1 - \tau} \right)^{n}} \right)T_{c}}\end{matrix}}} & {{FORMULA}\mspace{14mu} 6}\end{matrix}$

In some embodiments, it may be necessary or desirable to optimize boththe licensed and unlicensed band resource allocation to either haveswitching between the bands when one is congested or aggregation when ahigher data rate may be required. In configurations of system 100wherein SeNB 106 may serve one or more SUEs 108 as well as one or moreSNs 110, system 100 may determine how the data transmission rate thatmay be attained by SeNB 106, over licensed and/or unlicensed bands, maybe divided among SUEs 108 in the downlink.

Referring again to FIG. 2, each user equipment may request a variety ofdata services, with each service having different quality of service(“QOS”) requirements. In some embodiments, system 100 may use the QOSrequirements of SUEs 108 to determine minimum threshold rates for eachSUE 108. Within system 100, this rate may be attained over the licensedand/or unlicensed bands. In some embodiments, this determination may bemade by SeNB 106, as described in more detail above with reference toFIG. 1. FORMULA 7 below illustrates an example approach for this jointoptimization.

$\begin{matrix}{\mspace{545mu}{{FORMULA}\mspace{14mu} 7}} & \; \\\begin{matrix}{{Maximize}\mspace{14mu}\left\{ {\alpha,R_{u\; d}} \right\}} & {\sum\limits_{i = 1}^{S_{1}}\left\lbrack {{\alpha_{i}B_{d}\psi_{l\; d}^{(i)}} + R_{{ud}\;}^{(i)}} \right\rbrack} \\{{subject}\mspace{14mu}{to}} & {{\sum\limits_{i = 1}^{S_{1}}R_{ud}^{(i)}} \leq {R_{AP} - {\sum\limits_{k = 1}^{S_{2}}R_{wd}^{(k)}}}} \\\; & {{{{\alpha_{i}B_{d}\psi_{ld}^{(i)}} + R_{ud}^{(i)}} \geq {\overset{\_}{r}}_{sd}^{(i)}},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{R_{md}^{(j)} \geq {\overset{\_}{r}}_{m}^{(j)}},{j = 1},\ldots\mspace{14mu},M} \\\; & {{{\sum\limits_{i = 1}^{S_{1}}\alpha_{i}} \leq {\overset{\_}{\alpha} - \alpha_{m}}} = {\overset{\_}{\alpha}}_{s}} \\\; & {{0 \leq \alpha_{i} \leq 1},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{R_{ud}^{(i)} \geq 0},{i = 1},\ldots\mspace{14mu},S_{1}}\end{matrix} & \;\end{matrix}$

The approach illustrated in FORMULA 7 may maximize the sum of downlinkthroughputs over licensed and unlicensed bands for all SUEs 108. Thefirst constraint illustrated divides the extra capacity that may beattained by SeNB 106 (denoted R_(AP)) among SUEs 108. In order not tocause congestion on the unlicensed band, in some embodiments SeNB 106may serve all active SNs 110 first and determine downlink transmissionin the unlicensed band to some or all of the S₁ SUEs 108 depending onthe extra capacity on the unlicensed band. In other embodiments, SeNB106 may serve some or all of the S₁ SUEs 108 first and determinedownlink transmission in the unlicensed band to some or all of theactive SNs 110 depending on the extra capacity of the unlicensed band.The second constraint represents the QOS requirements of each SUE 108.The fourth constraint uses the parameter M, which denotes the totalnumber of MUEs 104 in system 100.

In the same or alternative embodiments, it may be more desirable toformulate the optimization problem as a linear programming problem. Thismay lead to the example approach illustrated in FORMULAS 8-15 below.FORMULA 8 is similar to FORMULA 3, wherein the QOS constraints for MUEs104 are rewritten in terms of the optimization variable of FORMULA 7.

$\begin{matrix}\begin{matrix}{R_{md}^{(j)} = {{\alpha_{m}^{(j)}B_{d}\eta_{b}\eta_{c}{\log_{2}\left( {1 + \frac{P_{m}{h_{j}}^{2}}{N_{o\; l}\eta_{s}}} \right)}} - \left( {\alpha_{m}^{(j)}B_{d}\eta_{b}\eta_{c}} \right.}} \\{\left. \left\lbrack {{\log_{2}\left( {1 + \frac{P_{m}{h_{j}}^{2}}{N_{o\; l}\eta_{s}}} \right)} - {\log_{2}\left( {1 + {\frac{P_{m}{h_{j}}^{2}}{N_{o\; l} + {P_{s}{I_{j}}^{2}}}\eta_{s}}} \right)}} \right\rbrack \right)\alpha_{s}} \\{= {C_{m\; 2}^{(j)} - {C_{m\; 1}^{(j)}{\sum\limits_{i = 1}^{S_{1}}{\alpha_{i}.}}}}}\end{matrix} & {{FORMULA}\mspace{14mu} 8}\end{matrix}$

FORMULA 9 below groups the optimization vectors α and R_(ud) to define asingle optimization vector, x. FORMULA 10 then rewrites the coefficientvectors f.x=[α ₁α₂ . . . α_(S) ₁ R _(ud) ⁽¹⁾ R _(ud) ⁽²⁾ . . . R _(ud) ^((S) ¹⁾]_(2S) ₁ _(×1) ^(T).  FORMULA 9f=[B _(d)ψ_(ld) ⁽¹⁾ B _(d)ψ_(ld) ⁽²⁾ . . . B _(d)ψld^((S) ¹ ⁾1_(S) ₁_(×1)]_(2S) ₁ _(×1) ^(T).  FORMULA 10

In FORMULA 10, the notation 1_(S1×1) may refer to a column vector of S1entries that are equal to 1. The desired inequality constraints may bemodeled by the matrix A and the vector b, as shown below in FORMULA11-12. The parameters r_(ud) and γ from FORMULA 12 are defined inFORMULA 13-14.

$\begin{matrix}{A = \begin{bmatrix}0_{S_{1} \times 1} & 1_{S_{1} \times 1} \\{{diag}\left( {{- B_{d}}\psi_{ld}} \right)} & {{diag}\left( {- 1_{S_{1} \times 1}} \right)} \\1_{S_{1} \times 1} & 0_{S_{1} \times 1}\end{bmatrix}_{{({S_{1} + 2})} \times 2\; S_{1}}} & {{FORMULA}\mspace{14mu} 11}\end{matrix}$where the notation diag(y) is used to refer to a diagonal matrix whosediagonal entries are the entries of the vector y.

$\begin{matrix}{b = \left\lbrack {{\overset{\_}{r}}_{ud} - {\overset{\_}{r}}_{sd}^{(1)} - {{\overset{\_}{r}}_{sd}^{(2)}\mspace{14mu}\ldots}\mspace{14mu} - {{\overset{\_}{r}}_{sd}^{(S_{1})}\mspace{14mu}\min\left\{ {\min_{j\;\gamma}^{(j)}{,{\overset{\_}{\alpha}}_{s}}} \right\}}} \right\rbrack_{2\; S_{1} \times 1}^{T}} & {{FORMULA}\mspace{14mu} 12} \\{\mspace{79mu}{{\overset{\_}{r}}_{ud} = {R_{AP} - {\sum\limits_{k = 1}^{S_{2}}R_{w}^{(k)}}}}} & {{FORMULA}\mspace{14mu} 13} \\{\mspace{79mu}{\gamma^{(j)} = \frac{{\overset{\_}{r}}_{m}^{(j)} - C_{m\; 2}^{(j)}}{C_{m\; 1}^{(j)}}}} & {{FORMULA}\mspace{14mu} 14}\end{matrix}$

The lower and upper bounds of the optimization variable x may defined,respectively, in FORMULAS 15-16 below.l _(b)=0_(2S) ₁ _(×1),  FORMULA 15u _(b)=[1_(S) ₁ _(×1) r _(ud)·1_(S) ₁ _(×1)]_(2S) ₁ _(×1).  FORMULA 16

One advantage of implementing this approach is that the linearprogramming approach may be solved more efficiently. In system 100 inwhich the particular configuration may require frequent, dynamicupdates, this more efficient solution may be desired.

In addition to optimizing the downlink in the licensed and unlicensedbands as described in more detail above, in some embodiments it may benecessary or desirable to also jointly optimize the downlink and uplinkin the unlicensed band. As described in more detail above, thethroughput for a given wireless medium may be heavily dependent on thenumber of devices contending for access to the medium, including SeNB106. In some implementations of an unlicensed band (e.g., WiFi), thetotal number of devices contending for access depends not only ondevices contending for downlink, but also on devices contending foruplink access.

In some embodiments, optimizing both downlink and uplink activities inthe unlicensed band allows system 100 to more efficiently and flexiblycontrol the activities within the unlicensed band while also increasingthroughput for both uplink and downlink. In configurations in which theswitching and/or aggregation determinations are made centrally (e.g., bySeNB 106), it may allow further efficiencies in processing.

Similar to the issues faced in optimizing downlink in the unlicensedband, an approach presenting an optimization problem for the uplink maybe used. As with downlink, SeNB 106 must satisfy the varying QOSrequirements for each SUE 108. With uplink, SeNB 106 may be configuredto control the number of SUEs accessing the unlicensed band. In someembodiments, this may be performed through the use of a binaryindicator. FORMULA 17 below illustrates the number of devices accessingthe unlicensed band access point (e.g., SeNB 106). In FORMULA 17, theparameter u_(i) represents the example binary indicator that indicateswhether a given device is connected in uplink to the unlicensed band.

$\begin{matrix}{n = {S_{2} + {\sum\limits_{i = 1}^{S_{1}}u_{i}} + 1}} & {{FORMULA}\mspace{14mu} 17}\end{matrix}$

Within system 100, increasing the number of activated uplinktransmission may help offload some uplink traffic to the unlicensed bandand therefore help satisfy QOS requirements. This may be offset by thefact that the larger the number n of devices accessing the unlicensedband, the lower the throughput for each individual device. This maycounteract the ability of system 100 to meet the QOS requirements forother devices. FORMULA 18 illustrates an example approach for maximizingfour parameters: (1) the fraction of bandwidth assigned to a given SUE108 in downlink, α; (2) the throughput of the given SUE 108 in theunlicensed band in downlink, R_(ud); (3) the fraction of bandwidthassigned to the given SUE 108 in uplink, β; and (4) the number ofdevices to which access to the unlicensed band has been granted.

$\begin{matrix}\begin{matrix}\underset{\{{\alpha,R_{ud},\beta,u}\}}{maximize} & {\sum\limits_{i = 1}^{S_{1}}\left\lbrack {{\alpha_{i}B_{d}\psi_{l\; d}^{(i)}} + R_{ud}^{(i)} + {\beta_{i}B_{u}\psi_{l\; u}^{(i)}} + {u_{i}R_{uu}^{(i)}}} \right\rbrack} \\{{subject}\mspace{14mu}{to}} & {{\sum\limits_{i = 1}^{S_{1}}R_{ud}^{(i)}} \leq {R_{AP} - {\sum\limits_{k = 1}^{S_{2}}R_{wd}^{(k)}} -}} \\\; & {{\delta_{u,}\max} \leq {\sum\limits_{i = 1}^{S_{1}}\left\lbrack {u_{i} - {u_{i}\left( {t - 1} \right)}} \right\rbrack} \leq {\delta_{u,}\max}} \\\; & {{{{\alpha_{i}B_{d}\psi_{ld}^{(i)}} + R_{ud}^{(i)}} \geq {\overset{\_}{r}}_{sd}^{(i)}},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{R_{md}^{(j)} \geq {\overset{\_}{r}}_{m}^{(j)}},{j = 1},\ldots\mspace{14mu},M} \\\; & {{{{\beta_{i}K_{u}\psi_{l\; u}^{(i)}} + R_{uu}^{(i)}} \geq {\overset{\_}{r}}_{su}^{(i)}},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {R_{MBS} \geq {\overset{\_}{r}}_{MBS}} \\\; & {{{\sum\limits_{i = 1}^{S_{1}}\beta_{i}} \leq {\overset{\_}{\beta} - \beta_{m}}} = {\overset{\_}{\beta}}_{s}} \\\; & {{\sum\limits_{i = 1}^{S_{1}}u_{i}} \leq U_{\max}} \\\; & {{{\sum\limits_{i = 1}^{S_{1}}\alpha_{i}} \leq {\overset{\_}{\alpha} - \alpha_{m}}} = {\overset{\_}{\alpha}}_{s}} \\\; & {{0 \leq \alpha_{i} \leq 1},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{0 \leq \beta_{i} \leq 1},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{R_{ud}^{(i)} \geq 0},{i = 1},\ldots\mspace{14mu},S_{1}} \\\; & {{u_{i} = 0},1,{i = 1},\ldots\mspace{14mu},S_{1}}\end{matrix} & {{FORMULA}\mspace{14mu} 18}\end{matrix}$

FORMULA 18 makes use of the following parameters, as described in moredetail above: (1) α_(i)B_(d)ψ^((i)) _(ld), which represents thethroughput of a given SUE 108 in downlink in the licensed band; (2)β_(i)B_(u)ψ^((i)) _(lu), which represents the throughput of a given SUE108 in uplink in the licensed band; (3) R^((i)) _(ud), which representsthe throughput of a given SUE 108 in downlink in the unlicensed band;(4) u_(i)R^((i)) _(uu), which represents the throughput of a given SUE108 in uplink in the unlicensed band; (5) R^((k)) _(wd), whichrepresents the throughput of a given SN 110 in downlink; and _((6) R)^((k)) _(wu), which represents the throughput of a given SN 110 inuplink.

As described in more detail above, the throughput in the unlicensed bandmay depend heavily on the number of devices attempting to access theunlicensed band. As described with respect to FORMULA 18, this number(as represented by the parameter u may be variable). FORMULA 19 belowillustrates an approach for approximating the variable n by a constantvalue n′. In the approach illustrated in FORMULA 19, the valueu_(i)(t−1) may be associated with a decision of the unlicensed banduplink transmission at the previous decision instant.

$\begin{matrix}{n^{\prime} = {S_{2} + {\sum\limits_{i = 1}^{S_{1}}{u_{i}\left( {t - 1} \right)}} + 1}} & {{FORMULA}\mspace{14mu} 19}\end{matrix}$

Using the approximation described above with reference to FORMULA 19,the optimization problem may be reduced to a mixed integer programmingproblem. Using existing approaches (e.g., Branch-and-Bound, Gomory'sCutting Plane, Lagrangaian Relaxation, Benders Decomposition, etc.),system 100 may efficiently solve the optimization problem.

FIG. 3 illustrates a block diagram of a system 300 for switching and/oraggregating communication over the licensed and/or unlicensed bands, inaccordance with certain embodiments of the present disclosure. System300 includes admission control module 302, resource allocation module304, packet scheduling module 306, WiFi scheduling module 308, and LTEscheduling module 310.

In some embodiments, the various modules of system 300 may beimplemented in hardware, software, firmware, and/or some combinationthereof. In the same or alternative embodiments, system 300 may beimplemented as part of SeNB 106, as described in more detail above withreference to FIG. 1-2. Alternatively, some or all of the modules ofsystem 300 may be distributed throughout various portions of system 100.

Although the modules of system 300 are illustrated as being discretemodules with discrete tasks, in some configurations of system 300 someor all of the modules may be grouped together in more, fewer, ordifferent modules. For example, admission control module 302 andresource allocation module 304 may be combined into a single module.

In some embodiments, resource allocation module 304 may be configured todetermine whether switching and/or aggregation of the licensed andunlicensed bands is currently feasible. For example, the data raterequirements for a given data service request may be too high for theswitching system to currently accommodate. Resource allocation module304 may be further configured to identify which particular servicerequest resulted in a determination of unfeasibility (e.g., byidentifying the particular SUE 108 issuing the service request). In someembodiments, admission control module 302 may be configured to denyadmission of certain SUEs 108. In the same or alternative embodiments,admission control module 302 may be configured to alter a QOSrequirement of certain SUEs 108 that resulted in the infeasibilitydetermination.

In some embodiments, system 300 may also include resource allocationmodule 304. As described in more detail above with reference to FIGS.1-2, optimization of communication at a small node for both licensed andunlicensed bands may include finding a feasible solution given thedownlink and uplink rate constraints (e.g., the two inputs denoted inFIG. 3), as described in more detail above with reference to FORMULA 18.Resource allocation module 304 may be configured to indicate toadmission control module 302 whether a feasible solution is available.In some embodiments, it may do so by communicating a feasible/infeasiblesignal (denoted as “F/I” in FIG. 3). For example, a value of zero mayindicate that there is no feasible solution, while a value of one mayindicate that there is a feasible solution. Resource allocation module304 may be further configured to provide admission control module 302with the identity of the devices for which the QOS requirements can notbe met (denoted as “inf_i” in FIG. 3). Admission control module 302 maythen use this information to decrease the corresponding QOS requirementsor deny the admission of that SUE 108.

In some embodiments, resource allocation module 304 may run itsoptimization routines periodically. For example, the time period betweenruns (T_(d)) may be calculated by N_(d) Transmission Time Intervals(“TTI”), where N_(d) may be a design parameter indicating how much time(in units of subframes, i.e., TTIs) may be required for the operation ofresource allocation module 304. As described in more detail above withreference to FIG. 1-2, the main outputs of the optimization routines maybe values indicative of the bandwidth allocation and available rates. Insome embodiments, they may also include the number of devices for whichto grant access to the small cell access point (e.g., SeNB 106), as wellas identifiers of spectral efficiency. For example, resource allocationmodule 304 may provide the vectors α and β, which may represent thefraction of licensed bandwidth in downlink and uplink, respectively, tobe allocated to SUE 108. Resource allocation module 304 may alsocommunicate the vector ψ_(ld), which may be associated with the spectralefficiency of each SUE 108. Resource allocation module 304 may alsocommunicate the vector R_(ud), which may represent the downlink rate onthe unlicensed band for each SUE 108.

In some embodiments, system 300 may also include packet schedulingmodule 306. Packet scheduling module 306 may be configured to determinehow much data to send over which communication band. For example, packetscheduling module 306 may use a bucketing approach for accumulating dataover a time T_(d), distributing the data segments into the appropriatelicensed or unlicensed bucket, and then sending the buckets to theappropriate communication band. In other configurations, otherscheduling methods may be implemented, such as a round-robin,first-com-first-served system, etc.

System 300 may also include WiFi scheduling module 308. In someembodiments, WiFi scheduling module 308 may be configured to take datapackets received from packet scheduling module 306 and deliver them tothe WiFi interface. In some configurations, WiFi scheduling module 308may also take certain measurements of the current state of the WiFiinterface for communication back to resource allocation module 304, asdescribed in more detail above with reference to FIGS. 1-2.

System 300 may also include a licensed band scheduling module such asLTE scheduling module 310. In some embodiments, LTE scheduling module310 may be configured to take data packets received from packetscheduling module 306 and deliver them to the LTE interface. In someconfigurations, LTE scheduling module 310 may also take certainmeasurements of the current state of the LTE interface for communicationback to resource allocation module 304, as described in more detailabove with reference to FIGS. 1-2.

In order to support the switching and/or aggregation operationsdescribed in more detail above with reference to FIGS. 1-3, system 100may need to implement some signaling between user equipment and thesmall cell controller.

FIG. 4 illustrates an example signaling diagram 400 for supporting theswitching and/or aggregation operations, in accordance with certainembodiments of the present disclosure. In some embodiments, signalingdiagram 400 includes user equipment (“UE”) 402. UE 402 may be anyelectronic device configured to communicate over the licensed band. Forexample, UE 402 may correspond to SUE 108 as illustrated above withreference to FIG. 1.

Signalling diagram 400 may also include a radio access network such asEvolved UMTS Terrestrial Radio Access Network (“EUTRAN”) 304. EUTRAN 304is the radio access network underlying the 3GPP standard. Otherconfigurations of systems 100, 300 may implement different radio accessnetwork(s) without departing from the scope of the present disclosure.

In example signaling diagram 400, UE 402 and EUTRAN 404 requirecoordination in order to implement the optimization routines describedin more detail above with reference to FIGS. 1-3. One example approachis to use the RRCConnectionReconfiguration message 406 andRRCConnectionReconfigurationComplete message 408 specified in the 3GPPstandard. By appending two additional bits, di and ui, to theRRCConnectionReconfiguration message, UE 402 and EUTRAN 404 maycoordinate activities. TABLE 2 below illustrates a set of example valuesfor these two additional bits, in addition to an example interpretationfor those values. As would be apparent to one of ordinary skill in theart, the precise approach for signaling between user equipment and radioaccess network base station may vary widely depending on the specificimplementation without departing from the scope of the presentdisclosure.

TABLE 2 d_(i) u_(i) Interpretation 0 0 Disable WiFi interface 0 1 EnableWiFi interface for uplink transmission only 1 0 Enable WiFi interfacefor downlink reception only 1 1 Enable WiFi interface for both uplinktransmission and download reception

Because the coordination operations may be concluded solely between theuser equipment and the radio access network base station, involvement bythe cellular provider's core network may be unnecessary and thereforereduce overhead processing time.

In addition to signaling between UE 402 and EUTRAN 404, system 100 mayin some embodiments also be configured to allow signaling between MBS102 and the small cell controller, e.g., SeNB 106. As described in moredetail above, with reference to FIGS. 1-3, and below with reference toFIGS. 5-6, it may be necessary or desirable to provide SeNB 106 withcertain values in order to more effectively control the intercellinterference. Three of those values are r _(m) ^((j)), α_(m) ^((j)), andr _(MBS). The first value, r _(m) ^((j)), may represent a minimum raterequirement of a given MUE 104 in downlink of the licensed band. Thesecond, α_(m) ^((j)), may represent a fraction of the licensed bandwidthassigned to the given MUE 104 in downlink. Finally, r _(MBS) mayrepresent a minimum rate of MBS 102 in uplink of the licensed band. SeNB106 may also be configured to make use of additional values. Forexample, SeNB 106 may be configured to incorporate values representativeof path losses between MUEs 104 and MBS 102.

In some embodiments, the small cell controller (e.g., SeNB 106) may beconfigured to receive certain of these values from MBS 102. For example,MBS 102 may be configured to signal the rate requirement r _(m) ^((j)).In some configurations, this signaling may be done by signaling the raterequirement after quantization in 12 bits starting with 10 kpbs with aresolution of 20 kpbs. This may allow system 100 to achieve a maximumvalue of up to 81.91 Mpbs for the minimum rate requirements. Dependingon the particular configuration of system 100, these values may vary toachieve the design characteristics of the particular configuration. Therate requirement value may be communicated for each MUE 104 in thevicinity of SeNB 106. This number of MUEs 104 (denoted as “M” in therate requirement notation) may be determined by MBS 102. For example,MBS 102 may determine the number of MUEs 104 reporting low ChannelQuality Indicator (“CQI”) values. In the same or alternativeconfigurations, the CQI values may be considered in combination withother values indicative of suffering from interference in the vicinityof SeNB 106. For example, M may have a range of zero to thirty-one,thereby requiring 5 bits for communicating the value.

In addition to the rate requirement, SeNB 106 may also make use of thefraction of bandwidth α_(m) ^((j)) assigned to a given MUE 104. Thisvalue may be reported to SeNB 106 from MBS 102. For example, each MUE104 may use four bits for each of the M MUEs 104 to communicate thebandwidth fraction. This may result in a resolution of 0.0625 for α_(m)^((j)). In other configurations, other values may be used for thesignaling in order to achieve the design characteristics of theparticular configuration.

In some embodiments, SeNB 106 may also make use of minimum rate value r_(MBS). In other embodiments, SeNB 106 may ignore this value or set itzero or a very small value such that the corresponding constraint withinthe relevant optimization problem may be satisfied. For example, inconfigurations in which SUEs 108 already have small transmission powersin uplink due to the proximity of SUEs 108 to SeNB 106, the interferencecaused by SUEs 108 in the uplink on MBS 102 may be negligible. However,in other configurations, the design characteristics may be such so as toconsider the minimum rate value. For example, r _(MBS) may becommunicated from MBS 102 to SeNB 106 in 12 bits starting with 100 kpbswith a resolution of 25 kpbs to achieve a maximum value of 102.45 Mpbs.Other configurations may use different values for the signaling in orderto achieve the design characteristics of the particular configuration.

In the same or alternative embodiments, SeNB 106 may also make use ofpath losses between MUEs 104 and MBS 102. For example, MBS 102 mayestimate the path loss by sending the uplink CQI to SeNB 106, asdescribed in more detail above and with reference to FIGS. 2-3. In someconfigurations, the CQI level may be represented in 4 bits per MUE 108.Other configurations may use different values for the signaling in orderto achieve the design characteristics of the particular configuration.SeNB 106 may then be able to estimate the path losses from the CQIinformation.

In embodiments in which multiple SeNBs 106 are communicatively coupled,more, fewer, or different values may be used to aid in the optimizationproblem. In such embodiments, SeNBs 106 may be configured to signal viasome other communication channel. For example, SeNBs 106 may beconfigured to communicate over a dedicated channel and/or through thebackhaul of the cellular service provider.

FIG. 5 is a flowchart of an example method 500 for determining whether auser equipment should have traffic switched to an unlicensedcommunication band, in accordance with certain embodiments of thepresent disclosure. In some embodiments, method 500 may include steps502-12. Although illustrated as discrete steps, various steps may bedivided into additional steps, combined into fewer steps, or eliminated,depending on the desired implementation.

In some embodiments, method 500 may begin at step 502, at which theoptimization routine may begin. As described in more detail above withreference to FIGS. 1-4, this may be instanced by the coming into rangeof a small cell control by a user, or (as described in more detail abovewith reference to FIG. 3) after the passage of a predetermined period oftime.

After beginning the process, method 500 may proceed to step 504. At step504, method 500 may determine whether or not the licensed band (e.g.,the LTE network) is sufficiently congested as to warrant an attemptedoptimization. If it is not sufficiently congested, method 500 may returnto step 502 to wait for another event (e.g., the passage of thepredetermined time period). If the network is sufficiently congested,method 500 may proceed to step 506.

At step 506, method 500 may determine whether the unlicensed band (e.g.,the WiFi band) has sufficient capacity to meet the demand, as describedin more detail above with reference to FIGS. 1-4. In some embodiments,certain data values may be useful in the determination made at step 506.For instance, average channel idle time, the number of active users,etc., may be used to make the determination. At step 512, thisinformation may be passed to step 506 for use in the determination, asdescribed in more detail above with reference to FIGS. 1-4. If theunlicensed band can meet the demand, method 500 may proceed to step 508.

At step 508, method 500 may select one or more appropriate bearer(s) andproper UE(s) for switching to and/or aggregating with the unlicensedband, as described in more detail above with reference to FIGS. 1-4.After selecting the bearers and UEs, method 500 may proceed to step 510,where method 500 may inform the UE(s) of the decision, as described inmore detail above with reference to FIG. 4.

In some embodiments, the steps of method 500 may be performed bysoftware, hardware, firmware, and/or some combination thereof. Forexample, the steps of method 500 may be performed by SeNB 106 of system100. In other embodiments, different steps may be performed by differentcomponents. For example, step 512—measuring the data values for use inthe optimization routines—may be performed by various components ofsystem 100.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments. As an illustrative example, method 500 may further includereceiving a response from the UE indicating whether the reconfigurationwas complete. As an additional illustrative example, method 500 mayfurther include indicating which UEs were responsible for the inabilityto meet the requested capacity.

FIG. 6 is a flowchart of an example method 600 for determining whether auser equipment should have traffic aggregated with traffic in anunlicensed communication band, in accordance with certain embodiments ofthe present disclosure. In some embodiments, method 600 may includesteps 602-12. Although illustrated as discrete steps, various steps maybe divided into additional steps, combined into fewer steps, oreliminated, depending on the desired implementation.

In some embodiments, method 600 may begin at step 602, at which theoptimization routine may begin. As described in more detail above withreference to FIGS. 1-4, this may be instanced by the coming into rangeof a small cell control by a user, or (as described in more detail abovewith reference to FIG. 3) after the passage of a predetermined period oftime.

After beginning the process, method 600 may proceed to step 604. At step604, method 600 may determine whether or not a UE has demanded a highthroughput link. If not, method 600 may return to step 602 to wait foranother event (e.g., the passage of the predetermined time period). Ifso, method 600 may proceed to step 606.

At step 606, method 600 may determine whether the unlicensed band (e.g.,the WiFi band) has sufficient capacity to meet the demand, as describedin more detail above with reference to FIGS. 1-4. In some embodiments,certain data values may be useful in the determination made at step 606.For instance, average channel idle time, the number of active users,etc., may be used to make the determination. At step 612, thisinformation may be passed to step 606 for use in the determination, asdescribed in more detail above with reference to FIGS. 1-4. If theunlicensed band can meet the demand, method 600 may proceed to step 608.

At step 608, method 600 may select one or more appropriate bearer(s) andproper UE(s) for switching to and/or aggregating with the unlicensedband, as described in more detail above with reference to FIGS. 1-4.After selecting the bearers and UEs, method 600 may proceed to step 610,where method 600 may inform the UE(s) of the decision, as described inmore detail above with reference to FIG. 4.

In some embodiments, the steps of method 600 may be performed bysoftware, hardware, firmware, and/or some combination thereof. Forexample, the steps of method 600 may be performed by SeNB 106 of system100. In other embodiments, different steps may be performed by differentcomponents. For example, step 612—measuring the data values for use inthe optimization routines—may be performed by various components ofsystem 100.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments. As an illustrative example, method 600 may further includereceiving a response from the UE indicating whether the reconfigurationwas complete. As an additional illustrative example, method 600 mayfurther include indicating which UEs were responsible for the inabilityto meet the requested capacity.

All examples and conditional language recited herein are intended forpedagogical objects to aid the reader in understanding the invention andthe concepts contributed by the inventor to furthering the art, and areconstrued as being without limitation to such specifically recitedexamples and conditions. Although embodiments of the present inventionshave been described in detail, it should be understood that variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. A small cell controller for aggregating wirelessdata transmitted to and from user equipment (UE) between a cellularnetwork and a noncellular network, the small cell controller comprising:a cellular interface to communicate data with the cellular network andreceive a plurality of values associated with the cellular network,wherein the plurality of values are based on a rate requirement; anoncellular interface to communicate data with the noncellular network;and an analyzer configured to: determine whether a portion of thewireless data may be transferred from the cellular network to thenoncellular network based at least on the plurality of values associatedwith the cellular network; determine a first portion of the noncellularnetwork to be allocated to the portion of the wireless data when theportion of the wireless data may be transferred; determine whether totransfer a portion of the wireless data from the cellular network to thenoncellular network based at least in part on a joint optimization ofdownlink traffic on a second portion of the noncellular network, uplinktraffic on a second portion of the noncellular network, downlink trafficon a third portion of the noncellular network, uplink traffic on a firstportion of the cellular network, downlink traffic on a second portion ofthe cellular network, and downlink traffic on a portion of the cellularnetwork; aggregating the portion of the wireless data from the cellularnetwork with data of the noncellular network; and coordinate activitiesbetween the UE and the small cell controller without communicating witha core network of the cellular network.
 2. The small cell controller ofclaim 1, wherein the analyzer is configured to determine whether totransfer a portion of the wireless data from the cellular network to thenoncellular network based at least in part on an analysis of intercellinterference.
 3. The small cell controller of claim 1, wherein the jointoptimization is based at least on a linear programming approach.
 4. Thesmall cell controller of claim 1, wherein the joint optimization isbased at least on a mixed integer programming approach.
 5. The smallcell controller of claim 1, wherein the cellular interface is configuredto provide a signal to user equipment, wherein the signal is configuredto notify the user equipment of data associated with the first portionof the noncellular network.
 6. The small cell controller of claim 5,wherein the data associated with the first portion of the noncellularnetwork comprises data to notify the user equipment to enable a userequipment noncellular interface.
 7. The small cell controller of claim1, wherein the noncellular interface is configured to determine a numberof devices allowed access to the noncellular network.
 8. The small cellcontroller of claim 1, wherein the coordinating comprises appending bitsto an RRCConnectionReconfiguration message that indicate whether toenable the noncellular interface and whether to enable uplinktransmission, downlink reception or both.
 9. A method of aggregating awireless data transmitted to and from user equipment (UE) between acellular network and a noncellular network, the method comprising:receiving a plurality of values associated with the cellular network,wherein the plurality of values are based on a rate requirement;determining whether to transfer a portion of the wireless data from thecellular network to the noncellular network based at least on theplurality of values associated with the cellular network; determining afirst portion of the noncellular network to be allocated to the portionof the wireless data when the portion of the wireless data may betransferred; determining whether to transfer a portion of the wirelessdata from the cellular network to the noncellular network based at leastin part on a joint optimization of downlink traffic on a second portionof the noncellular network, uplink traffic on a second portion of thenoncellular network, downlink traffic on a third portion of thenoncellular network, uplink traffic on a first portion of the cellularnetwork, and downlink traffic on a second portion of the cellularnetwork, and downlink traffic on a portion of the cellular network;aggregating the portion of the wireless data from the cellular networkwith data of the noncellular network; and coordinating activitiesbetween the UE and a small cell controller without communicating with acore network of the cellular network.
 10. The method of claim 9, whereinthe determining to transfer a portion of the wireless data from thecellular network to the noncellular network is based at least in part onan analysis of intercell interference.
 11. The method of claim 9,wherein the joint modification is based at least on a linear programmingapproach.
 12. The method of claim 9, wherein the joint modification isbased at least on a mixed integer programming approach.
 13. The methodof claim 9, further comprising providing a signal to user equipment,wherein the signal is configured to notify the user equipment of dataassociated with the first portion of the noncellular network.
 14. Themethod of claim 13, wherein the data associated with the first portionof the noncellular network comprises data to notify the user equipmentto enable a user equipment noncellular interface.
 15. The method ofclaim 9, further comprising determining a number of devices allowedaccess to the noncellular network.
 16. The method of claim 9, whereinthe coordinating comprises appending bits to anRRCConnectionReconfiguration message that indicate whether to enable thenoncellular interface and whether to enable uplink transmission,downlink reception or both.
 17. A small cell controller for aggregatingwireless data transmitted to and from user equipment (UE) between acellular network and a noncellular network, the small cell controllercomprising: a cellular interface to communicate data with the cellularnetwork and receive a plurality of values associated with the cellularnetwork, wherein the plurality of values are based on a raterequirement, the cellular interface configured to provide a signal touser equipment, the signal configured to notify the user equipment ofdata associated with the first portion of the noncellular network, thedata associated with the first portion of the noncellular networkcomprises data to notify the user equipment to enable a user equipmentnoncellular interface; a noncellular interface to communicate data withthe noncellular network; and an analyzer configured to: determinewhether a portion of the wireless data may be transferred from thecellular network to the noncellular network based at least on theplurality of values associated with the cellular network; determine afirst portion of the noncellular network to be allocated to the portionof the wireless data when the portion of the wireless data may betransferred; determine whether to transfer a portion of the wirelessdata from the cellular network to the noncellular network based at leastin part on a joint optimization of downlink traffic on a second portionof the noncellular network, uplink traffic on a second portion of thenoncellular network, downlink traffic on a portion of the cellularnetwork, downlink traffic on a third portion of the noncellular network,uplink traffic on a first portion of the cellular network, and downlinktraffic on a second portion of the cellular network; aggregating theportion of the wireless data from the cellular network with data of thenoncellular network; and coordinate activities between the UE and thesmall cell controller without communicating with a core network of thecellular network, the data to notify the user equipment comprising datato disable the noncellular interface, enable the noncellular interfacefor uplink transmission only, enable the noncellular interface fordownlink reception only, and enable the noncellular interface for bothuplink transmission and download reception.